Hi,
This is more of a Subversion question than a TortoiseSVN question, so this isn't the natural home for this query.
That said, the issue concerns an understanding of peg and operative revisions, within Subversion. The short answer is that the command you may want is the following:
svn list "file:///C:/Users/0046193/Desktop/TestRepo_delete/trunk/02_Folder_to_delete@r2"
More information can be found in the Subversion Red Book, in the section titled
"Peg and Operative Revisions".
Based on the Red Book description, the longer answer is that Subversion treats the folder added in revision 4 as a different item than the folder added at revision 2, even though they share the same name.
The command that you had translates as follows:
"Find the item named trunk/02_Folder_to_delete in the head of the repository and then list that item from revision 2".
However, that folder didn't exist in revision 2 - it was only added in revision 4, so an error is reported. Remember that items aren't the same just because they share the same name.
My suggested command translates as follows:
"Find the item named trunk/02_Folder_to_delete in revision 2 of the repository and then list that item".
That works because that folder did exist in revision 2 (where it was created), so it could be found and listed.
Hope this helps.